I had a working prototype, and charlieplexing worked, almost as intended. One part that was missing was the font. George Mason omitted this part in his patent, so we don't know how it was supposed to look, except maybe for one letter - M.
I watched a TechnologyConected video about the Numitron 7-segment displays. In the beginning, Alec showed the first variants of the now ubiquitous segmented displays. He mentioned a patent by George Mason dated 1898 and said that though it was the true alpha-numeric display the font it produced was "creepy". I love font design, calligraphy, and everything about letters and I was definitely against such a harsh description. I thought the font and the display itself as it was described in a drawing was beautiful! Anyway, I sent a link to the patent to a friend who happens to be a graphical designer and asked if I was wrong thinking that this thing has potential as a font. He said that it definitely looked interesting and unusual and later that day sent me a mock-up in figma where you could switch segments on and off and make letters. I was amused by this and though I had other projects to work on I thought it would be pretty simple but cool to bring this display to life.
Now we need a flip-dot version :)